In regards to Ivy Schools, they are generally ranked top 10 in most non-engineering subjects in the USA, including math, physics and economics. An Ivy grad is a reasonable guarantee that you are getting top class talent.
come to think of it, why is everyone on here so concerned with 'killing hollywood' lately? we should be killing the too-big-to-fail financial institutions.
Corruption between the two could be a driver to seek that dictatorship however...
I think the same kind of signaling is used at its fullest in big banks investment dpts. In most cases, what is actually done by e.g. quants is far from very sophisticated mathematically speaking. But you can more easily claim that what you do is complicated if most of your quants are from prestigious institutions. Having everyone coming from a similar set of cultural values also helps cohesion.